if installing the flooring directly on top of laminate in one room can this be use as an end piece for the doorways into other room?

Hello! No, the Landry Oak Quarter Round Floor Moulding is decorative moulding that is used to conceal expansion space between laminate flooring and a wall or around cabinetry. You will need to use a T-moulding in the doorway. Please review the Pergo Portfolio+ Landry Oak Installation Guide, available on the product page at Lowe's.com, for moulding installation procedures. Thanks for your interest! - Shanna